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52 lines
1.4 KiB
ReStructuredText
52 lines
1.4 KiB
ReStructuredText
.. _cmd-if:
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if - conditionally execute a command
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====================================
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Synopsis
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--------
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::
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if CONDITION; COMMANDS_TRUE...;
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[else if CONDITION2; COMMANDS_TRUE2...;]
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[else; COMMANDS_FALSE...;]
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end
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Description
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-----------
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``if`` will execute the command ``CONDITION``. If the condition's exit status is 0, the commands ``COMMANDS_TRUE`` will execute. If the exit status is not 0 and :ref:`else <cmd-else>` is given, ``COMMANDS_FALSE`` will be executed.
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You can use :ref:`and <cmd-and>` or :ref:`or <cmd-or>` in the condition. See the second example below.
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The exit status of the last foreground command to exit can always be accessed using the :ref:`$status <variables-status>` variable.
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Example
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-------
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The following code will print ``foo.txt exists`` if the file foo.txt exists and is a regular file, otherwise it will print ``bar.txt exists`` if the file bar.txt exists and is a regular file, otherwise it will print ``foo.txt and bar.txt do not exist``.
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::
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if test -f foo.txt
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echo foo.txt exists
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else if test -f bar.txt
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echo bar.txt exists
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else
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echo foo.txt and bar.txt do not exist
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end
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The following code will print "foo.txt exists and is readable" if foo.txt is a regular file and readable
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::
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if test -f foo.txt
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and test -r foo.txt
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echo "foo.txt exists and is readable"
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end
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